JP2001283751A - Cathode-ray tube apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube apparatus capable of eliminating disadvantages concerning withstand voltages, and forming good beam spot shapes in an entire area of a phosphor screen without increasing cost. SOLUTION: A main lens comprises a dynamic focus electrode G6, first auxiliary electrodes GM1, GM2, and a positive electrode G7, which are sequentially arranged in a traveling direction Z of an electron beam. A sub lens, which is formed on a cathode side K of the main lens, comprises a third grid G3, a fourth grid G4, and a fifth grid G5. The first auxiliary electrode GM1 is connected with the fourth grid G4, and connected with a voltage supply terminal R1-1 on a resistor R1 adjacent to the fourth grid G4. A fixed focus voltage Vf1 is applied to the third and fifth grids arranged on both sides of the fourth grid G4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly to a cathode ray tube having an electron gun assembly for performing dynamic astig compensation.

[0002]

2. Description of the Related Art In general, a color cathode ray tube apparatus has an in-line type electron gun assembly for emitting three electron beams, and deflects an electron beam emitted from the electron gun assembly to horizontally and vertically move on a phosphor screen. A deflection yoke for generating a deflection magnetic field for scanning. This deflection yoke forms an asymmetric magnetic field by a pincushion type horizontal deflection magnetic field and a barrel type vertical deflection magnetic field.

An electron beam passing through such an asymmetric magnetic field is affected by deflection aberration, that is, astigmatism contained in the deflection magnetic field, and the beam spot of the electron beam reaching the peripheral portion of the phosphor screen is distorted. Significantly degrades resolution. For this reason, as a means for solving the deterioration of resolution due to such a deflection aberration, a dynamic focus type electron gun assembly as disclosed in Japanese Patent Application Laid-Open No. 64-38947 has been developed.

[0004] As shown in FIG.
A dynamic focus electrode G5 to which the dynamic focus voltage Vd is applied, an anode electrode G6 to which the anode voltage Eb is applied, and an auxiliary electrode GM disposed therebetween.
1 and GM2 constitute a main lens ML. The auxiliary electrodes GM1 and GM2 are supplied with a voltage obtained by dividing the anode voltage Eb by using a resistor 100 arranged near the electron gun structure.

Thus, asymmetric lenses QL1 and QL2 are provided between the dynamic focus electrode G5 and the auxiliary electrode GM1, and between the auxiliary electrode GM2 and the anode electrode G6.
To form When dynamic focus is applied to the dynamic focus electrode G5 in order to deflect the electron beam to the peripheral portion of the phosphor screen, the asymmetric lens QL1 does not generate a horizontal lens effect and diverges only in the vertical direction. Generates lens action.

This electron gun structure is intended to correct the distortion of the electron beam spot at the periphery of the phosphor screen by such a lens action.

However, in such an electron gun assembly, by applying the dynamic focus voltage to the dynamic focus electrode G5, the AC component of the dynamic focus voltage is reduced due to the capacitance between the electrodes constituting the main lens ML. It is superimposed on the voltage applied to the auxiliary electrodes GM1 and GM2. As a result, the asymmetric lens QL1 formed between the dynamic focus electrode G5 and the auxiliary electrode GM1 does not have sufficient lens action, and the asymmetric lens QL2 formed between the auxiliary electrode GM2 and the anode electrode G6 is not suitable. The desired lens action occurs.

Therefore, there is a problem in that the distortion of the beam spot at the peripheral portion of the phosphor screen cannot be sufficiently corrected, and it becomes difficult to obtain good focus characteristics over the entire phosphor screen.

Also, as shown in FIG. 10, the main lens M
When L has two or more auxiliary electrodes (GM1 and GM2) to which a voltage is supplied by the resistor 100 disposed in the vicinity of the electron gun structure, the voltage supply terminals 110 and 120 on the resistor 100 are arranged close to each other. Doing so is disadvantageous in terms of withstand voltage.

That is, these auxiliary electrodes GM1 and G
Connect the voltage supply lead wire for supplying voltage to M2 with resistor 1
00, the voltage supply terminal 1 of the resistor 100
10 and 120 are auxiliary electrodes GM for work efficiency, respectively.
It is preferable to be near 1 and GM2. Therefore, when two or more auxiliary electrodes GM1 and GM2 are present, the two voltage supply terminals 110 and 120 are connected to the resistor 10
This means that they are arranged close to each other on zero.

However, when the two or more voltage supply terminals 110 and 120 are arranged in a close position on the resistor 100 in this way, the cathode line is connected between the two or more voltage supply terminals 110 and 120. Discharge or the like is likely to occur during the operation of the tube, causing a problem in withstand voltage.

In order to avoid such a problem, FIG.
1 is located at a position distant from the first auxiliary electrode GM1, that is, two focus electrodes G5 and G
7 is provided with the second auxiliary electrode G6 disposed between the first and second electrodes. The second auxiliary electrode G6 is connected to the first auxiliary electrode GM1, and is supplied with a voltage from a voltage supply terminal 110 provided on the resistor 100 near the second auxiliary electrode GM1. Thereby, the distance between the voltage supply terminals 110 and 120 of the two first auxiliary electrodes GM1 and GM2 can be substantially sufficiently separated, and the problem withstand voltage can be solved.

However, even with such a configuration,
Since it is necessary to separately provide the second auxiliary electrode G6 in the electron gun assembly, the total number of electrodes constituting the electron gun assembly is increased, and the cost is increased. In addition, the number of electron lenses formed in the electron gun structure also increases, and errors in the electron beam trajectory are likely to occur.

[0014]

As described above, in the configuration of the conventional electron gun assembly, the AC component of the dynamic focus voltage is superimposed on the voltage applied to the adjacent electrodes, and the dynamic focus voltage is applied to the electron lens formed by these electrodes. Undesirable lens action occurs, and it is difficult to sufficiently correct the distortion of the beam spot of the electron beam deflected to the periphery of the phosphor screen.

In the conventional electron gun assembly, when two or more auxiliary electrodes for supplying a voltage obtained by dividing the anode voltage by resistance using a resistor are arranged close to each other, the voltage supply terminals on the resistor are close to each other. This is disadvantageous in terms of withstand voltage.

Further, in order to eliminate disadvantages in withstand voltage, apart from a plurality of first auxiliary electrodes arranged close to each other,
A second auxiliary electrode is arranged at a position distant from them, one of the first auxiliary electrodes is electrically connected to the second auxiliary electrode, and the voltage is supplied to a resistor near the second auxiliary electrode. When the terminals are provided, the number of electrodes constituting the electron gun structure increases, which leads to an increase in cost and an increase in the number of electron lenses formed in the electron gun structure, resulting in an error in the electron beam trajectory. It will be easier.

As a result, the focus characteristic is deteriorated over the entire phosphor screen, and it becomes difficult to obtain a beam spot having a good shape.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to eliminate a disadvantage in withstand voltage and to provide a good beam spot over the entire area of a phosphor screen without increasing cost. An object of the present invention is to provide a cathode ray tube device capable of forming a shape.

[0019]

According to a first aspect of the present invention, there is provided a cathode ray tube device comprising: an electron beam forming unit for forming at least one electron beam; Gun having a main focusing lens unit for focusing the laser beam on the screen, and deflecting the electron beam emitted from the electron gun assembly to generate a deflection magnetic field for scanning in a horizontal direction and a vertical direction on the screen. And a deflection yoke, wherein the main focusing lens unit includes at least one focus electrode to which a first level constant focus voltage is applied, and a second level anode voltage higher than the first level. At least one anode electrode to be applied and a third voltage higher than a first level and lower than a second level obtained by dividing the anode voltage by a resistor through a resistor;
At least one first auxiliary electrode to which a level voltage is applied, and at least one dynamic focus electrode to which a voltage obtained by superimposing a dynamic focus voltage that fluctuates in synchronization with a deflection magnetic field generated by the deflection yoke is applied to the focus electrode And the main focusing lens unit comprises:
A final main focusing lens unit including the dynamic focus electrode, at least one first auxiliary electrode, and an anode electrode which are sequentially arranged at least along an electron beam traveling direction; At least one second auxiliary electrode connected to the first auxiliary electrode is provided on the electron beam forming unit side of the lens unit, and the induced voltage induced by the first auxiliary electrode of the final main focusing lens unit is reduced. An electrode to which a fixed voltage is applied is disposed in the vicinity of the second auxiliary electrode so as to perform the operation.

The cathode ray tube device according to the present invention is characterized in that the second auxiliary electrode is arranged so as to be sandwiched between a pair of the focus electrodes to which a constant focus voltage is applied.

According to a third aspect of the present invention, in the cathode ray tube device, the second auxiliary electrode has an electron beam opening formed corresponding to the electron beam formed by the electron beam forming section. When the average diameter of Φ is Φ and the electrode length is L, the relationship of 0.4 × Φ ≦ L ≦ 1.7 × Φ is established between them.

A cathode ray tube device according to a fourth aspect is characterized in that the second auxiliary electrode and a pair of the focus electrodes constitute a unipotential type sub lens unit.

According to a fifth aspect of the present invention, in the cathode ray tube device, the focus electrode forming the sub-lens portion and the dynamic focus electrode forming the final main focusing lens portion are arranged adjacent to each other, and between these electrodes. A multipole lens that fluctuates in synchronization with the deflection magnetic field is formed.

According to a sixth aspect of the present invention, in the cathode ray tube device, the lens strength is set in a horizontal direction and a vertical direction in a lens space formed by the first auxiliary electrode and the anode electrode constituting the final main focusing lens portion. And have different asymmetric lens components.

According to a seventh aspect of the present invention, in the cathode ray tube device, the asymmetric lens component has a lens function of diverging relatively vertically and converging horizontally.

In the cathode ray tube device according to the present invention, the lens strength is perpendicular to the horizontal direction in a lens space formed by the first auxiliary electrode and the dynamic focus electrode constituting the final main focusing lens unit. It is characterized by having different asymmetric lens components in different directions.

According to a ninth aspect of the present invention, in the cathode ray tube device, the asymmetric lens component has a lens function of diverging relatively vertically and converging horizontally.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the cathode ray tube device of the present invention will be described with reference to the drawings.

As shown in FIG. 3, the cathode ray tube device of the present invention, for example, a color cathode ray tube device, has a panel 1 and an envelope composed of a funnel 2 integrally joined to the panel 1. Panel 1 is located on its inner surface,
A phosphor screen 3 (target) composed of a striped or dot-shaped three-color phosphor layer that emits blue, green, and red light, and a large number of apertures mounted inside and opposed to the phosphor screen 3 are provided. And a shadow mask 4 having the same.

The funnel 2 is provided with three electron beams 6B, 6G, and 6R arranged in a line including a center beam 6G passing through the same horizontal plane and a pair of side beams 6B and 6R on both sides of the center beam 6G. An in-line type electron gun assembly 7 that emits light in the tube axis direction Z is provided. The in-line type electron gun assembly 7 is configured to decenter the positions of the side beam passage holes of the grid on the low voltage side and the grid on the high voltage side, which constitute the main lens unit, so that the phosphor screen 3 is formed.
Self-focus the three electron beams at the center of.

A deflection yoke 8 is mounted outside the funnel. The deflection yoke 8 generates a non-uniform deflection magnetic field for deflecting the three electron beams 6B, 6G, 6R emitted from the electron gun assembly 7 in the horizontal direction H and the vertical direction V. In the non-uniform deflection magnetic field, the deflection yoke is formed by a pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection magnetic field.

The three electron beams 6 B, 6 G, and 6 R emitted from the electron gun assembly 7 are focused on the corresponding phosphor layer on the phosphor screen 3 while being self-focused toward the phosphor screen 3. Then, these three electron beams are scanned in the horizontal direction H and the vertical direction V of the phosphor screen 3 by the non-uniform deflection magnetic field. Thereby, a color image is displayed.

As shown in FIG. 1, an electron gun assembly 7 applied to this cathode ray tube apparatus has a cathode K, a first grid G
1, second grid G2, third grid G3 (focus electrode), fourth grid G4 (second auxiliary electrode), fifth grid G5 (focus electrode), sixth grid G6 (dynamic focus electrode), seventh grid GM1 (First
An auxiliary electrode), an eighth grid GM2 (first auxiliary electrode), a ninth grid G7 (anode electrode), and a convergence cup C. These grids and convergence cups are arranged in this order along the traveling direction of the electron beam, and are supported and fixed by an insulating support (not shown).

The first grid G1 is grounded (or a negative potential V1 is applied), and the second grid G2 is
A low potential acceleration voltage V2 is applied. This acceleration voltage V2 is in the range of 500 V to 1 KV.

The third grid G3 and the fifth grid G5 are connected inside a tube, and are supplied with a constant middle potential first focus voltage Vf1 from outside the cathode ray tube. The first focus voltage Vf1 is a voltage corresponding to about 22% to 32% of an anode voltage Eb described later, and is, for example, 6 to 10 KV.

On the sixth grid G6, a dynamic focus in which an AC voltage Vd synchronized with a deflection magnetic field generated by a deflection yoke is superimposed on a second focus voltage Vf2 substantially equal to the first focus voltage Vf1 from outside the cathode ray tube. The voltage (Vf2 + Vd) is supplied. Like the first focus voltage Vf1, the second focus voltage Vf2 is a voltage corresponding to about 22% to 32% of the anode voltage Eb, for example, 6 to 10 KV. Also, the AC voltage V
d is from 0 V to 300 to 1500 in synchronization with the deflection magnetic field.
V.

The ninth grid G7 and the convergence cup C are connected, and an anode voltage Eb is supplied from outside the cathode ray tube. This anode voltage Eb is 25 to 35 KV
It is.

As shown in FIG. 1, a resistor R1 is provided near the electron gun assembly 7, and one end of the resistor R1 is connected to the ninth grid G.
7 and the other end is grounded outside the tube via a variable resistor VR. The resistor R1 has voltage supply terminals R1-1 and R1-2 for supplying a voltage to the grid of the electron gun assembly 7 at an intermediate portion thereof.

The fourth grid G4 and the seventh grid GM1 are connected in a pipe, and the fourth grid G4
Is connected to the voltage supply terminal R1-1 on the resistor R1. These fourth grid G4 and seventh grid G
M1 is connected to the anode voltage E via a voltage supply terminal R1-1.
A voltage obtained by dividing b by resistance, for example, a voltage of about 35 to 45% of the anode voltage Eb is supplied.

The eighth grid GM2 is connected to the voltage supply terminal R1-2 on the resistor R1 near the eighth grid GM2. The voltage obtained by dividing the anode voltage Eb by resistance, for example, a voltage of about 50% to 70% of the anode voltage Eb is supplied to the eighth grid GM2 via the voltage supply terminal R1-2.

The first grid G1 is a thin plate-shaped electrode, and has three small-diameter electron beam passage holes formed by drilling the plate surface. Second grid G
Reference numeral 2 denotes a thin plate-like electrode provided with three electron beam passage holes slightly larger than the hole diameter formed in the first grid G1.

The third grid G3 has a length 2 in the pipe axis direction Z.
It is formed by abutting the open ends of the individual cup-shaped electrodes. The end face of the cup-shaped electrode facing the second grid G2 has three slightly larger electron beam passage holes. The end face of the cup-shaped electrode facing the fourth grid G4 is provided with three large-diameter electron beam passage holes.

The fourth grid G4 has a length 2 in the pipe axis direction Z.
It is formed by abutting the open ends of the individual cup-shaped electrodes. The end face of the cup-shaped electrode facing the third grid G3 has three large diameter electron beam passage holes. The end face of the cup-shaped electrode facing the fifth grid G5 has three large diameter electron beam passage holes.

The fifth grid G5 has a length 3 in the pipe axis direction Z.
It is composed of one cup-shaped electrode and one plate-shaped electrode. The two cup-shaped electrodes on the fourth grid G4 side are:
The opening ends of the cup-shaped electrodes on the sixth grid G6 side are butted, and the opening ends of the cup-shaped electrodes on the sixth grid G6 side are thin plate-shaped. Matched with electrodes. The end faces of the three cup-shaped electrodes are provided with three large-diameter electron beam passage holes. The plate surface of the plate-shaped electrode facing the sixth grid G6 is provided with three vertically or circularly shaped electron beam passage holes extending in the vertical direction V.

The sixth grid G6 is composed of two cup-shaped electrodes and two plate-shaped electrodes having a short length in the tube axis direction Z. Open ends of the two cup-shaped electrodes on the fifth grid G5 side are respectively abutted, and open ends of the cup-shaped electrodes on the seventh grid GM1 side are abutted on thin plate-shaped electrodes. The plate-like electrode is abutted against a thick plate-like electrode.

The end face of the cup-shaped electrode facing the fifth grid G5 is provided with three horizontally long electron beam passage holes extending in the horizontal direction H. The end surface of the cup-shaped electrode on the seventh grid GM1 side has three large-diameter electron beam passage holes. The plate surface of the thin plate-shaped electrode is provided with three horizontally long, large-diameter electron beam passage holes extending in the horizontal direction H. The plate surface of the thick plate-like electrode facing the seventh grid GM1 has three large-diameter electron beam passages.

The seventh grid GM1 and the eighth grid GM
2 is constituted by a thick plate-like electrode. The plate surfaces of these plate electrodes are provided with three large-diameter electron beam passage holes.

The ninth grid G7 is composed of two plate-like electrodes and two cup-like electrodes. The thick plate-shaped electrode facing the eighth grid G8 is abutted against the thin plate-shaped electrode, the thin plate-shaped electrode is abutted against the end face of the cup-shaped electrode, and the two cup-shaped electrodes are respectively Open ends are butted.

The thick plate-like electrode facing the eighth grid G8 has three large-diameter electron beam passage holes. The thin plate-shaped electrode is provided with three horizontally elongated electron beam passage holes extending in the horizontal direction H. The end faces of the two cup-shaped electrodes are provided with three large-diameter electron beam passage holes.

The convergence cup C has an end face,
The end face of the cup-shaped electrode of the ninth grid G7 abuts. The end face of the convergence cup C is 3 mm in diameter.
Electron beam passage holes.

In the electron gun assembly 7 configured as described above, the cathode K, the first grid G1, and the second grid G
2 forms an electron beam generator. The second grid G2 and the third grid G3 form a prefocus lens for prefocusing the electron beam generated from the electron beam generator.

The third grid G3, the fourth grid G4, and the fifth grid G5 form a sub-lens for further pre-focusing the pre-focused electron beam. Sixth grid G6, seventh grid GM1, eighth grid GM2,
And the ninth grid G7 forms the final focusing main lens on the pre-focused electron beam phosphor screen.

Between the fifth grid G5 and the sixth grid G6, a quadrupole lens whose lens strength changes due to a dynamic focus voltage Vd that fluctuates according to the amount of electron beam deflection is formed.

Between the sixth grid G6 and the seventh grid GM1 forming the main lens, a dynamic focus voltage Vd which fluctuates according to the deflection amount of the electron beam is used.
As the lens strength changes, the horizontal direction H and the vertical direction V
Thus, an asymmetric lens having a different lens strength is formed. This asymmetric lens has a lens function of relatively diverging in the vertical direction V and focusing in the horizontal direction H.

The eighth grid G forming the main lens
An asymmetric lens having a different lens strength between the horizontal direction H and the vertical direction V is formed between M2 and the ninth grid G7. This asymmetric lens diverges relatively in the vertical direction V,
It has a lens function of focusing in the horizontal direction H.

As described above, the fourth grid G4 is arranged so as to be sandwiched between the pair of focus electrodes to which the fixed first focus voltage Vf1 is supplied, that is, the third grid G3 and the fifth grid G5. The seventh grid GM1 constituting the main lens is electrically connected to the fourth grid G4. For this reason, the superimposition rate of the AC voltage component of the dynamic focus voltage superimposed on the grid GM1 and the grid GM2 in the main lens can be reduced.

That is, a comparison between the equivalent circuit of the present invention and that of the present invention is as shown in FIGS. FIG.
FIG. 5 is an equivalent circuit of the main lens in the conventional electron gun structure shown in FIG. 5, and FIG. 5 is an equivalent circuit of the main lens in the electron gun structure shown in FIG. Based on these equivalent circuits, the superimposition ratio of the dynamic focus voltage applied to the dynamic focus electrode to the grid GM1 and the grid GM2 according to the related art and the present invention was calculated. Conventionally, the superimposition rate on the grid GM2 was 66% and the superimposition rate on the grid GM1 was 33%, whereas according to the embodiment of the present invention, the grid GM2
The superimposition rate on the grid GM1 was 26%, and the superimposition rate on the grid GM1 was 13%.

Conventionally, in an electron gun assembly including an auxiliary electrode for applying a voltage to a main lens by resistance division, by applying a dynamic focus voltage to a dynamic focus electrode, a capacitance between the preceding and succeeding electrodes is applied to the auxiliary electrode. , The AC component of the dynamic focus voltage is superimposed. At this time, since the superimposition ratio of the dynamic focus voltage is extremely large, an asymmetric lens formed between the dynamic focus electrode and the auxiliary electrode, and
Problems such as undesired lens operation occurring in the asymmetric lens formed between the auxiliary electrode and the anode electrode occur. As a result, distortion of the beam spot around the phosphor screen cannot be completely corrected, and it becomes difficult to obtain good focus characteristics over the entire phosphor screen.

On the other hand, in the electron gun assembly according to this embodiment, even when a dynamic focus voltage is applied to the dynamic focus electrodes, the alternating current superimposed on the grids GM1 and GM2 via the capacitance between the electrodes. The superimposition rate of the components can be reduced.

Therefore, the dynamic focus electrode G
6 and the grid GM1, and between the grid GM2 and the anode electrode G7, it is possible to suppress an undesired lens operation, and it is possible to obtain good focus characteristics over the entire phosphor screen.

Further, with the configuration as in this embodiment, a plurality of auxiliary electrodes constituting the main lens, that is, a voltage supply terminal on a resistor for supplying a voltage to the grids GM1 and GM2 are arranged apart from each other. be able to. For this reason, it is possible to solve the problem of withstand voltage during the operation of the cathode ray tube device.

Further, by adopting the structure as in this embodiment, the number of electrodes does not increase as compared with the conventional electron gun structure as shown in FIG. That is, according to this embodiment, the conventional sub-lens electrode G4 is configured as the second auxiliary electrode G4, and the first auxiliary electrode GM in the main lens is formed.
1 is connected. For this reason, an increase in cost can be suppressed, and an error in the electron beam trajectory due to an increase in the number of electron lenses can be prevented.

Incidentally, in the conventional electron gun structure as shown in FIG. 11, the grids G3, G
4 and G5 were high-low-high, respectively. However, in the electron gun assembly according to this embodiment, the grid G
3, G4, and G5 form a unipotential type acceleration sub-lens. It is difficult for the acceleration type sub lens to obtain a sufficient lens strength as compared with the conventional sub lens, and there is a problem in adopting it as it is.

Therefore, in this embodiment, the average diameter of the opening of the fourth grid G4 (second auxiliary electrode) is Φ, the electrode length in the tube axis direction Z is L, and It is structured so that the relationship holds.

0.4 × Φ ≦ L ≦ 1.7 × Φ By doing so, in the electron gun assembly according to this embodiment, the beam spot diameter of the electron beam reaching the phosphor screen is designed to be the minimum. Can be.

That is, FIG. 6 is a diagram showing the relationship between the electrode length G4L (mm) of the fourth grid G4 and the magnification M in the electron gun assembly using the acceleration type sub-lens. Here, the magnification M is a ratio of the image point size on the phosphor screen to the object point size in the electron beam generator.

At this time, the length of the electron gun in the electron gun structure is 22.5 mm. Here, the electron gun length is a third grid G that substantially determines the length of the entire electron gun structure.
3 is a length along the tube axis direction Z from the end face on the second grid G2 side to the end face on the seventh grid GM1 side of the sixth grid G6. The main lens has a diameter of 6.0 mm.
It is.

In FIG. 6, the diameter Φ of the electron beam passage hole formed in the fourth grid G4 constituting the acceleration type sub lens is shown.
Was 2 mm, 3 mm, and 4 mm, the magnification M with respect to the electrode length G4L of the fourth grid G4 was calculated.
As a result, when such an acceleration type sub lens is employed, a maximum value exists in the magnification M when the electrode length G4L is increased, and the maximum value of the magnification M increases as the hole diameter Φ increases. It can be seen that the electrode length G4L tends to shift in the increasing direction. At this time, there is an optimum value between the electrode length G4L and the hole diameter Φ, and the magnification M is maximized when the electrode length G4L and the hole diameter Φ are substantially equal.

FIG. 7 shows an electrode length G4L of the fourth grid G4 in an electron gun assembly using this acceleration type sub lens.
FIG. 6 is a diagram illustrating a relationship between an aberration coefficient Cso and a (mm). Here, the aberration coefficient Cso is a coefficient corresponding to the spherical aberration in the lens system including the acceleration type sub lens and the main lens.

At this time, the electron gun length in the electron gun assembly is 22.5 mm, and the lens diameter of the main lens is φ
6.0 mm.

In FIG. 7, the diameter Φ of the electron beam passage hole formed in the fourth grid G4 constituting the acceleration type sub lens is shown.
Was 2 mm, 3 mm, and 4 mm, the aberration coefficient Cso for the electrode length G4L of the fourth grid G4 was calculated. As a result, when such an acceleration type sub-lens is employed, when the electrode length G4L is increased, a minimum value exists in the aberration coefficient Cso, and the minimum value of the aberration coefficient Cso increases as the hole diameter Φ increases. Therefore, it can be seen that the electrode length G4L tends to shift in the increasing direction. At this time, an optimum value exists between the electrode length G4L and the hole diameter Φ, and the aberration coefficient Cso becomes minimum when the electrode length G4L and the hole diameter Φ become substantially equal.

FIG. 8 shows an electrode length G4L of a fourth grid G4 in an electron gun assembly using this acceleration type sub lens.
It is a figure which shows the relationship of the beam spot size SS (mm) on the center part of a phosphor screen with respect to (mm).

At this time, the electron gun length in the electron gun assembly is 22.5 mm, and the lens diameter of the main lens is φ
6.0 mm.

In FIG. 8, the diameter Φ of the electron beam passage hole formed in the fourth grid G4 constituting the acceleration type sub lens is shown.
Was 2 mm, 3 mm, and 4 mm, the beam spot size SS with respect to the electrode length G4L of the fourth grid G4 was calculated. As a result, when such an acceleration type sub-lens is employed, a minimum value exists in the beam spot size SS when the electrode length G4L is increased, and the minimum value of the beam spot size SS is such that the hole diameter Φ is large. It can be seen that there is a tendency for the electrode length G4L to shift in the increasing direction as the length of the electrode length increases. At this time, the electrode length G4L
When the electrode length G4L is substantially equal to the hole diameter Φ, the beam spot size SS
Is minimal.

On the other hand, in the conventional sub-lens (high-low-high), the characteristics of the magnification, the aberration coefficient, and the beam spot size with respect to the electrode length as described above are obtained by increasing the electrode length of the fourth grid. , There is no minimum and maximum value,
Change in one direction.

FIG. 9 shows that the electrode length G4L of the fourth grid G4 is changed to the diameter G of the electron beam passage hole formed in the fourth grid G4 in the electron gun assembly using the acceleration type sub lens.
It is a graph which shows the relationship of spot size SS% normalized by the minimum spot size to G4L / G4Φ divided by 4Φ.

At this time, the graphs A, B and C show the case where the electron gun length in the electron gun assembly is 22.5 mm and the lens aperture of the main lens is φ6.0 mm, and the graphs of the fourth grid G4 respectively. The case where the hole diameter Φ is 2 mm, 3 mm, and 4 mm is shown.

Graphs D, E, and F show the case where the electron gun length in the electron gun structure is 16.9 mm and the lens aperture of the main lens is φ6.0 mm, and the fourth is the fourth.
The case where the hole diameter Φ of the grid G4 is 2 mm, 3 mm, and 4 mm is shown.

Further, the graphs G, H and I show the case where the electron gun length in the electron gun assembly is 22.5 mm and the lens diameter of the main lens is φ8.0 mm, and the hole diameter of the fourth grid G4 is respectively. The case where Φ is 2 mm, 3 mm, and 4 mm is shown.

In general, the design of the spot size is limited to 10% down from the best size. In view of this, the design range is 110% or less when the minimum spot size is 100%. Becomes That is, the electron beam spot can be designed to have a minimum minimum size by giving the following relationship: 0.4 × Φ ≦ L ≦ 1.7 × Φ.

Further, the characteristics of the spot size SS% with respect to G4L / G4Φ shown in FIG. 9 tend not to change so much depending on the length of the electron gun and the diameter of the grid constituting the main lens. The range does not fluctuate significantly.

Therefore, if the electron gun assembly is equipped with the accelerating sub-lens satisfying the above-described conditions, it is possible to obtain an optimum beam spot size.

The effects of the present invention are not limited to this.

Before the electron beam enters the main lens, the speed of the electron beam is accelerated by the accelerating sub-lens composed of the third, fourth and fifth grids (the conventional low-high-low sub-lens). The lens has the advantage that the electron beam speed is reduced) and the chromatic aberration component received by the main lens is smaller than in the conventional case. Further, even with the same electron gun length, there is an advantage that the dynamic focus voltage can be reduced because the focus voltage is relatively low.

In the above-described embodiment, of the grids constituting the main lens, two grids are supplied with a voltage from a resistor, and each grid is supplied with a voltage via a separate voltage supply terminal. However, the present invention is not limited to this example.

That is, as shown in FIG. 2, a main lens is composed of a dynamic focus electrode G6 to which a dynamic focus voltage is supplied, an anode electrode G7 to which an anode voltage is supplied, and a single lens disposed therebetween. And the first auxiliary electrode GM1. In such a configuration, the first auxiliary electrode GM1 is connected to the second auxiliary electrode G
4 and a voltage is supplied from a single voltage supply terminal R1-3 on the resistor R1.

In such an electron gun assembly, the surface of the dynamic focus electrode G6 facing the first auxiliary electrode GM1,
Dynamic focus electrode G6 of first auxiliary electrode GM1
The surface facing the anode G7 and the surface facing the first auxiliary electrode GM1 of the anode G7 have electron beam passage holes common to the three electron beams.

Thus, similarly to the above-described embodiment, even when the dynamic focus voltage is applied to the dynamic focus electrode G6, the AC component superimposed on the first auxiliary electrode grid GM1 via the capacitance between the electrodes. Can be reduced.

For this reason, the dynamic focus electrode G
6 and the first auxiliary electrode GM1, and between the first auxiliary electrode grid GM1 and the anode electrode G7, it is possible to suppress an undesired lens operation, so that good focus can be achieved over the entire phosphor screen. Properties can be obtained.

A voltage supply terminal on a resistor for supplying a voltage to the auxiliary electrode grid GM1 forming the main lens is connected to one.
Therefore, the problem of withstand voltage during the operation of the cathode ray tube device can be solved.

Further, since the number of electrodes can be reduced, an increase in cost can be suppressed, and an error in the electron beam trajectory due to an increase in the number of electron lenses can be prevented.

[0092]

As described above, according to the present invention, it is possible to form a favorable beam spot shape over the entire area of the phosphor screen without increasing the cost while eliminating the disadvantage in withstand voltage. A simple cathode ray tube device can be provided.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view schematically showing an embodiment of an electron gun assembly applied to a cathode ray tube device of the present invention.

FIG. 2 is a vertical sectional view schematically showing another embodiment of the electron gun assembly applied to the cathode ray tube device of the present invention.

FIG. 3 is a horizontal sectional view schematically showing a configuration of a cathode ray tube device of the present invention.

FIG. 4 is a diagram for explaining an equivalent circuit of a main lens in a conventional electron gun assembly.

FIG. 5 is a diagram for explaining an equivalent circuit of a main lens in the electron gun assembly shown in FIG. 1;

FIG. 6 is a diagram showing an electrode length G4L (m) of a fourth grid G4 in an electron gun assembly using the acceleration type sub lens.
It is a figure which shows the relationship of magnification M with respect to m).

FIG. 7 is a diagram showing an electrode length G4L (m) of a fourth grid G4 in an electron gun assembly using the acceleration type sub lens.
It is a figure which shows the relationship of the aberration coefficient Cso with respect to m).

FIG. 8 shows an electrode length G4L (m) of a fourth grid G4 in an electron gun assembly using the acceleration type sub lens.
FIG. 9 is a diagram showing a relationship between the beam spot size SS (mm) on the center portion of the phosphor screen and m).

FIG. 9 is a diagram illustrating an electron gun assembly using an acceleration type sub lens, in which an electrode length G4L of a fourth grid G4 is changed to a hole diameter G4Φ of an electron beam passage hole formed in the fourth grid G4.
6 is a graph showing a relationship between a spot size SS% normalized by a minimum spot size and G4L / G4Φ divided by.

FIG. 10 is a diagram schematically showing a configuration of an electron gun assembly including a main lens corresponding to the equivalent circuit shown in FIG. 4;

FIG. 11 is a view schematically showing a configuration of another conventional electron gun assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 2 ... Funnel 3 ... Phosphor screen 4 ... Shadow mask 5 ... Neck 6 (B, G, R) ... Electron beam 7 ... In-line type electron gun structure 8 ... Deflection yoke K ... Cathode G1 ... First grid G2 ... Second grid G3 Third grid (focus electrode) G4 fourth grid (second auxiliary electrode) G5 fifth grid (focus electrode) G6 sixth grid (dynamic focus electrode) GM1 seventh grid (first Auxiliary electrode) GM2: Eighth grid (first auxiliary electrode) G7: Ninth grid (anode electrode) C: Convergence cup R1: Resistor

Claims (9)

[Claims] 1. An electron gun assembly having at least one electron beam forming unit for forming an electron beam, a main focusing lens unit for focusing the electron beam on a screen, and electrons emitted from the electron gun assembly. A deflection yoke for deflecting a beam to generate a deflection magnetic field for scanning in a horizontal direction and a vertical direction on a screen, wherein the main focusing lens unit has a first level constant focus voltage. At least one focus electrode to which is applied,
At least one anode electrode to which a second level anode voltage higher than the first level is applied, and a third level voltage higher than the first level and lower than the second level obtained by dividing the anode voltage by a resistor through a resistor. And at least one dynamic focus electrode to which a voltage obtained by superimposing a dynamic focus voltage that fluctuates in synchronization with a deflection magnetic field generated by the deflection yoke is applied to the focus electrode. Wherein the main focusing lens section is a final main focusing lens configured by the dynamic focus electrode, at least one of the first auxiliary electrodes, and the anode electrode, which are sequentially arranged at least along an electron beam traveling direction. And a first auxiliary electrode that is in contact with the electron beam forming unit side of the final main focusing lens unit. A fixed voltage is applied near the second auxiliary electrode so as to reduce an induced voltage induced in the first auxiliary electrode of the final main focusing lens unit. A cathode ray tube device comprising electrodes. 2. The cathode ray tube device according to claim 1, wherein the second auxiliary electrode is disposed so as to be sandwiched between a pair of the focus electrodes to which a fixed focus voltage is applied. 3. The second auxiliary electrode has an electron beam opening formed corresponding to an electron beam formed by the electron beam forming unit, wherein the average diameter of the opening is Φ, and 3. The cathode ray tube device according to claim 1, wherein, when the length is L, a relationship of 0.4 × Φ ≦ L ≦ 1.7 × Φ is established between them. 4. The cathode ray tube device according to claim 2, wherein said second auxiliary electrode and a pair of said focus electrodes form a unipotential type sub-lens portion. 5. A focus electrode forming the sub-lens portion and a dynamic focus electrode forming the final main focusing lens portion are arranged adjacent to each other, and fluctuate between these electrodes in synchronization with the deflection magnetic field. The cathode ray tube device according to claim 1, wherein a multipole lens is formed. 6. The lens space defined by the first auxiliary electrode and the anode electrode constituting the final main focusing lens portion has an asymmetric lens component having different lens strengths in a horizontal direction and a vertical direction. 6. The method according to claim 1, wherein
The cathode ray tube device according to any one of the above. 7. The cathode ray tube apparatus according to claim 6, wherein said asymmetric lens component has a lens function of relatively diverging in a vertical direction and converging in a horizontal direction. 8. A lens space formed by said first auxiliary electrode and said dynamic focus electrode constituting said final main focusing lens portion has an asymmetric lens component in which lens strength is different in a horizontal direction and a vertical direction. The cathode ray tube device according to claim 1, wherein: 9. The cathode ray tube apparatus according to claim 8, wherein said asymmetric lens component has a lens function of diverging relatively vertically and converging horizontally.